Question: $ {-4\cdot \left[ \begin{array}{cc} -1 & 0 \\ 1 & -2 \\ 1 & 3 \end{array} \right]=}$
The Strategy To multiply a matrix by a scalar, we multiply each term of the matrix by the scalar. Multiplying each term $ {\begin{aligned}-4\cdot \left[\begin{array}{rr} {-1} & {0} \\ {1} & {-2} \\ {1} & {3} \end{array}\right]&=\left[\begin{array}{rr} -4\cdot{-1} & -4\cdot{0} \\ -4\cdot{1} & -4\cdot{-2} \\ -4\cdot{1} & -4\cdot{3} \end{array}\right] \\\\&=\left[\begin{array}{rr} {4} & {0} \\ {-4} & {8} \\ {-4} & {-12} \end{array}\right]\end{aligned}}$ Summary ${-4\cdot \left[ \begin{array}{cc} -1 & 0 \\ 1 & -2 \\ 1 & 3 \end{array} \right]=\left[ \begin{array}{cc} 4 & 0 \\ -4 & 8 \\ -4 & -12 \end{array} \right]}$